Bladder cancer is a common cancer with an estimated 67,160 new cases and 13,750 deaths in 2007. Most patients with non-muscle-invasive (superficial) cancers are initially treated with cystoscopic resection sometimes followed by intravesical therapy with bacillus Calmette-Guerin (BCG) solution. This solution contains live, weakened bacteria that stimulate the immune system to kill cancer cells in the bladder. The doctor will typically use a catheter to put the BCG solution in the bladder, and the patient needs to hold the solution in the bladder for at least about two hours. BCG bladder cancer treatment is usually done once a week for six weeks. BCG is a non-specific and irritating agent that has been in use for more than 30 years with little change. BCG lacks acceptable efficacy and has many side effects and limited tolerability. Some of the side-effects of BCG treatment include, but are not limited to, irritation of the bladder; an urgent need to urinate; the need to urinate frequently; pain, especially when urinating; fatigue; blood in the urine; nausea; a low-grade fever; and chills.
Moreover, many patients with non-invasive bladder cancer have a recurrence, with a recent meta-analysis reporting a recurrence rate of 39% after BCG therapy. In patients with high risk non-invasive bladder cancer, recurrence after intravesical BCG is very common with a recurrence rate in excess of 50%.
Accordingly, there is a need for effective non-invasive methods for treating bladder cancer.